The present invention relates generally to information recording/reproducing apparatus, and more particularly to such an information recording/reproducing apparatus for verifying or confirming the information recorded on a disc-like recording medium such as a magnetic disc and an optical disc.
Recently, in accordance with high-speed operation and high performance of computers, high-speed operation and high performance of peripheral equipment are required. Particularly, it is necessary for secondary storages such as a magnetic disc drive and an optical disc drive to reduce the access time while ensuring high reliability so as to increase the data transfer speed and the capacity. Thus, recent approaches involve increasing the rotational speed of the recording medium, reducing the weight of the recording/reproducing head and increasing the track pitch and the frequency for densification or an increase in the recording density. To improve the reliability of data written on the recording medium, it is usually to perform a write-and-verify operation to read out the written data in order to check whether the data is normally readable, whether the number of data errors such as bit inversion is below a standard value and whether the read-out data are correct. A conventional write-and-verity operation for an information recording/reproducing apparatus is described hereinbelow with reference to FIG. 1 for a better understanding of this invention. FIG. 1 illustrates a general arrangement of an optical disc system. In FIG. 1, a controller illustrated at numeral 3 includes a buffer memory 4 for immediately storing data transferred through a host interface 2 from a host computer 1. After the start of the data storage process in the buffer memory 4, the stored data are successively supplied to an EDAC 5 in units of data corresponding to one sector of a disc-like recording medium 8 where an error correction code is added thereto. The EDAC 5 acts as a bit error detection and correction circuit in which a predetermined bit is inserted into the data in accordance with an adequate calculation equation so as to find the error bit position when an error such as the bit inversion occurs on reproduction. Subsequently, the data from the EDAC 5 are supplied through a MODEM 6 to a drive unit 7 so as to be written on the recording medium 8. The MODEM 6 functions as a modulation and demodulation circuit to perform the modulation for recording data onto the optical disc and to perform the demodulation of the signal read out from the optical disc so as to obtain the original data before the recording. The optical disc recording medium has thereon a spiral track or coaxial track. Each track corresponds to one revolution of the optical disc being divided with equal angles into sectors each of which is the minimum recording block (element) and the one-time-recorded data being recorded over a plurality of sectors. A sector address and a track address for indicating the sector position on the optical disc are recorded in advance at the head portion of each of the sectors. For performing the write-and-verify operation, the data stored in the buffer memory 4 are required to be left until the verification is completed for the sector in which the data is written. In response to a problem resulting from verification, the data left in the buffer memory 4 are again transferred to the drive unit 7 so as to be written in a different sector of the recording medium 8. FIG. 2 shows a line of sectors on which data are written. For example, case all data to be recorded is 50 Kbytes, the capacity of the buffer memory 4 is 32 Kbytes and the capacity of each of the sectors on the recording medium 8 is 0.5 Kbytes. Of this 50 Kbytes, the 32 Kbyte data are first transferred thereto from the host computer 1 in FIG. 1. This process is then followed by an interruption of the transferring operation. The 32 Kbyte data stored in the buffer memory 4 are successively transferred to the drive unit 7 so as to be recorded in sectors m to m+63 of the recording medium 8 as illustrated by a in FIG. 2. Subsequently, the controller 3 causes the drive unit 7 to move in a radial direction of the recording medium 8 to perform the seeking operation in which the read-out address is checked to determine whether it is coincident with a target address set at the front side of the record-started sector m, as illustrated by b in FIG. 2. The drive unit 7 reads out the data in the sectors m to m+63 as illustrated by c in FIG. 2. The read-out data are transferred to the controller 3 which in turn, checks the qualities (bit error, level of the read-out signal) of the read-out data for each sector. If there is a problem, the data of buffer memory 4 corresponding to the sector are again transferred to the drive unit 7 to be written into an area disposed as a substitute for the sector. Thereafter, the portion of the buffer memory 4 corresponding to the sector is released. On the other hand, if there is no problem, the subject portion of the buffer memory 4 corresponding to the sector is released. On the other hand, if there is no problem, the subject portion of the buffer memory 4 is directly released. To the released portion of buffer memory 4, the next data are transferred from the host computer 1. After completion of the verification for the sectors m to m+63, the controller 3 causes the drive unit 7 to seek the front side of the sector m+63 as illustrated by d in FIG. 2. Here, during the standby for rotation as illustrated by e in FIG. 2, preparation is made for the next recording operation. Thereafter, the remaining 18 Kbyte data are similarly transferred through the EDAC 5 and the MODEM 6 to the drive unit 7 so as to be recorded in sectors after the sector m+63 as illustrated by f' in FIG. 2. Subsequently, in response to a command from the controller, the drive unit 7 seeks the front side of the sector m+64 as illustrated by q in FIG. 2 to read out the recorded data for verification as illustrated by h in FIG. 2. In FIG. 2, illustrations corresponding to the standby for rotation between the seeking b, q and the verification c, h are omitted for brevity.
According to the above-described write-and-verify operation, a quick switching operation to the recording for the sectors after the sector m+63 after the completion of the verification for the sectors m to m+63 becomes difficult because of generation of standby for rotation, generally one and more revolutions. Actually, the undesirable seeking operation and standby operation as illustrated by d and e in FIG. 2 are required. The number of the undesirable operations increases as the data amount increases and the effective capacity of the buffer memory 4 is reduced.
There is another problem which arises with such a write-and-verify operation, however, in that difficutly is encountered to quickly perform the switching operation between the verifying operation and the recording operation, thus standby time for the rotation operation of the recording medium is necessitated deteriorating the performance of the information recording/reproducing apparatus.